1. Technical Field
This invention relates in general to electronic communications and, more particularly, to error correction using a Viterbi decoder.
2. Description of the Related Art
Many electronic devices use error correction techniques in conjunction with data transfers between components and/or data storage. Error correction is used in many situations, but is particularly important for wireless data communications, where data can easily be corrupted between the transmitter and the receiver. In some cases, errant data is identified as such and retransmission is requested. Using more robust error correction schemes, however, errant data can be reconstructed without retransmission.
One popular error correction technique uses Viterbi decoding to detect errors in a data stream from a convolution encoder. A Viterbi decoder determines costs associated with multiple possible paths between nodes. After a specified number of stages, the node with the minimum associated cost is chosen, and a path is traced back through the previous stages. The data is decoded data based on the selected path.
Actual implementations of Viterbi decoding use dedicated hardware, because the decoding is computationally intensive. More and more devices, however, are turning to DSPs (digital signal processors) to handle the computational chores. Additional circuitry dedicated to Viterbi decoding on a DSP is undesirable, because it adds to the cost of the DSP and the power consumed by the DSP.
Accordingly, a need has arisen for a method and apparatus for performing Viterbi decoding in software.